The funny thing about qunari is that the boss dies faster than a saarebas.
The boss is vulnerable to phys damage, thus he gets "rekt" fairly quicky if you have a reaver/archer or anything that does heavy phys damage.
A saarebas can wipe out an entire party with the spirit dots/jumps/barriers/cc. The 25k hp on perilous does not help with that. That's NM hp range on perilous units.
I'm also under the impression that the spearmen hit much harder than their archer counterparts from other factions, but they hit less often.
Also to note, the spirit dot from saarebas behaves similarly to the fire dots - sometimes it does normal damage, e.g. 1 tick every x seconds, sometimes ticks 4-5-6 times in an instant. Not fun. It ticks for about 150 with my 70 willpower.
The shield guys also seem to hit harder, as I got hit for 400 on perilous on my avvar from their melee swing (when they become vulnerable from the front), whereas the usual damage range is about 200 ish on other factions.
The damage overall seems much higher compared to other factions, as i can faceroll anything on perilous, but i did wipe a couple of times from qunari because of the huge incoming damage.